Description Usage Arguments Details Value References See Also Examples

The efficiency factor is a dimensionless statistic which directly relates predictions to observed data.

1 | ```
EF(o, p)
``` |

`o` |
vector of observed values |

`p` |
vector of corresponding predicted values |

Two time series are compared. `'EF'`

is an overall measure
of similarity between fitted and observed values. Any model giving a
negative value cannot be recommended, whereas values close to one
indicate a 'near-perfect' fit.

`EF` |
efficiency factor |

Nash, J. E. and Sutcliffe, J. V. (1970) River flow forecasting through conceptual models part I - A discussion of principles. Journal of Hydrology, 10, 282-290.

Mayer, D. G. and Butler, D. G. (1993) Statistical Validation. Ecological Modelling, 68, 21-32.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 | ```
# a constructed example
x <- seq(0, 2*pi, 0.1)
y <- 5 + sin(x) # a process
o <- y + rnorm(x, sd=0.2) # observation with random error
p <- y + 0.1 # simulation with systematic bias
plot(x, o); lines(x, p)
EF(o, p)
# observed and measured data with non-matching time intervals
data(phyto)
obsb <- na.omit(obs[match(sim$t, obs$t), ])
simb <- sim[na.omit(match(obs$t, sim$t)), ]
EF(obsb$y, simb$y)
``` |

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